It's still too early to tell how Venezuela's shape-shifting tax structure will affect ConocoPhillips, Houston's largest corporation and the third-biggest U.S. energy company.

James Mulva, the company's chairman and CEO, told reporters after Wednesday's annual shareholder meeting that it is studying the new tax increase Venezuelan President Hugo Chavez announced Monday.

Mulva had planned to meet with Venezuela's energy minister, Rafael Ramirez, in Houston last week at the Offshore Technology Conference.

But Ramirez unexpectedly canceled his appearance, so Mulva said he hopes to meet with him in Caracas in coming weeks.

"What I know is simply what has been announced in the media. We have a good personal relationship with minister Ramirez, and I look forward to going down and talking with him," he said.

Last Monday, Chavez and Ramirez announced a new 33.3 percent tax — double the current rate — on all oil operations in the country that targets foreign operators, including ConocoPhillips, Exxon Mobil, BP and Chevron.

In the heavy-oil Orinoco belt where ConocoPhillips has significant interests, the income tax rate will jump to a hefty 50 percent, up from 34 percent.

"We don't have anything to discuss with the companies. The companies have to adjust," Ramirez said, according to an Associated Press report.

As Venezuelan interests have been thrown into limbo, ConocoPhillips is pushing forward in Russia.

The company has a 17.1 percent interest in Lukoil, Russia's largest oil company, but Mulva announced that stake would be 20 percent before year-end.

ConocoPhillips has also been short-listed as a potential partner with Gazprom to develop liquefied natural gas from the Shtokman field under the Barents Sea.

Mulva said Gazprom has indicated concession winners will be announced by the end of this month.

The primary market for Shtokman LNG, which could begin deliveries as early as 2010, would be the United States.

At the annual meeting, Mulva stressed to shareholders that fueling U.S. consumers through both oil and natural gas is the fundamental reason that ConocoPhillips exists.

He pointed to the company's track record of reinvesting net income earned over the last three years.

That money has been funneled into new exploration and production, as well as into refining.